It is often important to track or monitor at least the general location of entities at a work site or other type of environment. The entities that might be tracked at a site can be objects and/or personnel. For example, automobile dealerships frequently misplace vehicles and keys, and the size of some of these dealerships makes it difficult to determine where specific personnel are located. The constant problems associated with finding vehicles on a lot, and the keys necessary to operate them, as well as determining whether specific salespersons are at the facility and their location wastes time and reduces revenues, profits, and often adversely impacts customer satisfaction.
A salesperson at an automobile dealership may inadvertently put the keys to a car that is on the sales lot in a pocket and leave the site, perhaps on a test drive with another customer, or to go home. When another salesperson tries to find the keys on a peg board or some other designated repository for the vehicle keys, he finds that they are missing, and it is not evident who may have taken them or where they can be found. Furthermore, a customer may drop off a car for repair and upon returning to pickup the car, find that the repair shop is not sure where the car has been temporarily parked after being repaired, or the service manager may not be able to readily determine where the keys to the customer's vehicle have been placed. Clearly, the time required to resolve these matters relating to missing or misplaced entities reduces efficiency and may lead to lost sales or dissatisfied customers.
This problem is not limited to automotive dealerships. Nor are the entities that may need to be tracked limited to salespeople, vehicle keys, and vehicles. However, the following discussion is primarily directed to that specific type of business, since a solution to the problem of tracking the general location of personnel, vehicles, and vehicle keys is generally applicable to other types of applications and businesses.
At least in regard to preventing loss of keys for vehicles at a dealership, one approach that has been developed employs an electronic lockbox to hold the key for a vehicle. The lockbox hangs on the outside of a window on the vehicle, held in place when the window is rolled up. A salesperson or other individual that needs to access the key for a vehicle inserts an identification card into a slot on the lockbox and enters a personal identification number (PIN). If authorized, the lockbox opens, to enable the vehicle key to be accessed. Data are retained indicating the date, time, person accessing the key, and other information of interest in tracking the use of the vehicle for customer test drives, etc. The data are provided to a central monitoring station that can produce reports related to the vehicle activity. While this approach ensures that the person accessing the key for a vehicle is identified, in the event that the key is not returned to the lockbox after a use of the vehicle for a test drive or other purpose, the lockbox approach does not determine the relative position of each vehicle on the lot and cannot track the nominal position of personnel at the site. Also, the lockbox cannot determine if the vehicle key was transferred to another person at the site, which can make it difficult to locate a key that has been handed off to another salesperson. In addition, the lockbox solution poses a security risk, because the storage of keys with a vehicle makes theft potentially easier.
Another approach has been developed that uses radio frequency identification (RFID) tags that are temporarily mounted on each of the vehicles in a dealer's inventory. Infrastructure units, which communicate with the vehicle mounted RFID tags, are permanently mounted at various positions around the dealer lot, e.g., on lighting poles and are coupled to a central server. The server monitors signals from the RFID tags to determine the location of each vehicle on the lot, which is displayed in a webpage within a browser program on a computer display. There is no provision in this prior art system for tracking personnel, keys, or other types of entities besides vehicles. Also, it appears that the RFID tags on vehicles only communicate with the infrastructure units on the light poles, which can limit the effectiveness of the system for locating a vehicle that is at a remote corner of the lot, at some distance from the nearest permanently mounted infrastructure unit.
Yet another prior art system employs what is referred to as a “real time” location system that includes tags attached to vehicles that transmit a Wi-Fi signal to fixed Wi-Fi receivers, which is the equivalent of using Wi-Fi as a form of RFID, rather than to more typical RFID readers. This system employs a “time distance of arrival” triangulation approach to determine the location of a vehicle based on the slight differences in time required for a Wi-Fi signal transmitted from the tag on a vehicle to arrive at different Wi-Fi receivers mounted at various locations on a dealer's lot. The receivers are powered either directly (e.g., by batteries, or by AC line power), or by power-over-Ethernet conveyed through an Ethernet communication link, or by solar cells that can recharge a battery in the receiver. The Ethernet links convey the received signal times to a central server that determines the location of vehicles on a lot. There is again no provision for tracking other types of entities, such as keys or dealer personnel with this system and it requires that a substantial number of permanently fixed Wi-Fi receivers be mounted around the dealer lot to determine a vehicle location with a desired accuracy.
Another prior art system can identify automobiles that are driven in to a service lane by a customer seeking service on the vehicle. This system uses passive RFID tags that are permanently affixed to the customer's vehicle when it is sold to the customer or when the customer initially brings the vehicle in for servicing. The system detects the specific vehicle and displays a welcome to the customer on a flat panel display; however, this system does not track the location of the vehicle after it leaves the service lane.
Clearly, there are functions that each of the prior art systems do not provide and potential issues that can arise in regard to the limited functions that they do provide. It would thus be desirable to develop a system and procedure for tracking a plurality of different types of entities at a site that makes use of a network of interactive RFID tags that are each associated with a different entity. Each RFID tag should be able to periodically transmit a signal to other of the RFID tags that enables the general location of the entity with which it is associated to be determined. If a specific type of entity is in motion, the signal should be transmitted more frequently, to enable tracking of the entity as it moves about on the site, enters the site, or leaves the site.